Like so:

use Time::Local qw/timegm_nocheck/;

my $date_string = "2005301";    # The 301st day of 2005
my ($year,$julian_day) = $date_string =~ /^(\d\d\d\d)(\d\d\d)$/;
my $gmt = timegm_nocheck 0,0,0,$julian_day,0,$year;
# ...  do something with the gmt value
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Way back in the days of perl4, timelocal.pl (from whence Time::Local is derived) did no validation of the numbers since it is a straight numeric calculation that does not depend on how many days there are in a given month or how many hours in a day, etc. timegm_nocheck and timelocal_nocheck implement the modern-day equivalents of this idea.

But, you'd know this if you'd read the documentation

I don't think I'd use timegm with a Julian date.

Jan 1st 1970 has a Julian date of 2440587. Surely you can just subtract that from the Julian date you have and then multiply by the number of seconds in a day to get the number of seconds since the epoch. This, of course, assumes that your computer uses 1970-01-01 00:00:00 as its epoch.

Julian dates and julian days are different things. The latter is just the number of days since the start of the year. Jan 1 is julian day 1, Feb 1 is julian day 32, Feb 2, day 33, and so on.

duff

Julian days and Julian dates are subtley different things as the Wikipedia article indicates. But Julian day doesn't mean what you think it means. Granted, it's quite a common error. But it's still an error :)

--
<http://dave.org.uk>

"The first rule of Perl club is you do not talk about Perl club."
-- Chip Salzenberg